Investigation of the Causes of Building Collapse in Residential Structures in Lagos State (2018 to 2023)

Building collapse in Lagos State remains a recurring public safety crisis, and systematic investigation of its causes from documented incidents between 2018 and 2023 is essential for targeted preventive action. This study investigated the causes of 32 documented building collapse incidents in Lagos State between January 2018 and December 2023, using case study analysis of official investigation reports, newspaper records, Lagos State Building Control Agency enforcement data, and 40 interviews with structural engineers, surveyors, and building control officials. Each collapse incident was categorised by building type, age, location, number of floors, and primary cause as determined from investigation records. Results showed that residential buildings accounted for 78% of all collapse incidents. Structural overloading through unauthorised additional floors was the primary cause in 44% of cases. Poor construction quality due to substandard materials and inadequate supervision accounted for 28% of collapses. Structural modification without engineering advice caused 16% of incidents. Building age was not the primary factor in most collapses (mean age at collapse: 11.4 years). Poor or absent professional supervision was identified as a contributing factor in 81% of all cases. The study concludes that building collapse in Lagos State is predominantly caused by human error and regulatory non-compliance, and recommends strengthened enforcement of professional supervision requirements and mandatory structural integrity inspection at each construction stage.

Keywords: building collapse, residential buildings, Lagos State, structural failure, building control